High-speed steel



UNITED STATES PATENT OFFICE Elmer n. Welch, McKeesport,

Pittsburgh, Pa, Sterling Steel Company,

Firth,

Pennsylvania No Drawing. Application June 13, 1939,

Serial No. 278,903

6 Claims. This invention relates to high-speed steel of molybdenum type.

In an application for Letters Patent, filed J anuary 21, 1939, Serial No. 252,214, we have disclosed the discovery that boron may advantageously be included in the mix for steel of this type.

It is our discovery that, boron being pres ent in an amount that, in the twenty examples there given, ranges from 0.10 to 0.91% of the iron content, chromium may be entirely eliminated; and that, if chromium be eliminated, or if (being present) it is present in quantity not exceeding 1.50% 01 the iron content, a steel is produced that is tree of any tendency to deterlorate in heat treatment, and a steel that possesses the desirable qualities characteristic of the type.

Our present invention relates to the same subject-matter and, more specifically, to the inclusion in the mix of copper,

together with nickel.

, e In accordance with this invention, an alloy may contain the following elements within the percentages given (the percentages bein the iron content):

Vanadium Molybdenum Copper Nickel g relative to Percent 0.10 to Up to 0.05 to It may, additionally, contain chromium, if the chromium content does not exceed 1.50% of the iron content.

The foregoing table, recalculated to include iron, and'giving to nickel the minimum value as hereinafter specified, may

be repeated as follows:

Percent 0.28 to 0.05 to 0.09 to 0.24 t0 0.09 to 0.44 to 0.05 to and Lewis Gerald assignors to Firtha corporation of Following are examples of particular steels of the invention:

The remainder of these compositions will be understood to be substantially of iron, together with such other alloying elements and impurities as are sometimes found in alloy composi- 'tions of this type.

Silicon and manganese in small quantities are inevitable ingredients of the mix, and they have their recognized values. Their presence in small quantities may be taken for granted. It is the other components named that give character to the particular steels, and to these other ingredients the claims are directed. The silicon and manganese and other elements adventitiously present do not disturb the essential composition.

The hardening temperatures of these steels range from about 1700" F. to 2300" F. The range of drawing temperatures, at which secondary hardness is developed, is from 800 F. to 1200 F.

It has been found that thepresence of copper in these steels stabilizes the molybednum, and prevents its volatilization; it also retards the formation of craters that tend to occur back of the cutting edge, and it lowers the forging temperature. 35

It appears from examination of tools after use, that the addition of copper to a high-speed steel containing boron (and in which the chromium content is less than 1.50% of the iron content) has efiect in a particularly low galling property under the chip, as shown by the smooth condition of the edge of the tool after cutting. Nickel, present with the copper, improves the steel in the matters specified; that is to say, in the hardening and drawing temperatures.

Of the specimens whose analyses are given above, Nos. I and II, of relatively low carbon, are peculiarly suited to use where strength and toughness are of greater importance than cutting quality, as in die work. Nos. III-VIII are suitable as material for lathe tools. Their performance in such service will be found to be better by twenty to thirty percent than the familiar 5 1841 high-speed tool steel.

In the foregoing table percentages are given with relation to the iron content. Taking the essential elements (as specified above) of these specimen steelscarbon, vanadium, molybde- 10 num, copper, nickel, boron, and iron, and reducing to percentages of the whole, we have Va Mo Cu Ni B Fe 36 42 5. 69 1. 50 98' 39 90.71 51 75 7. 74 1. 67 2. 32 28 86. 73 64 1. 35 8. 61 2. 98 1. 45 21 84. 75 68 95 6. 69 2. 63 1. 34 24 87. 47 71 1. 34 6. 94 3. 68 1. 72 18 85. 53 85 1. 4B 7. 04 1. 76 96 17 87. 73 VII 89 2. 18 6. 86 2. 54 60 14 86. 78 20 VIII 1.03 2. 66 7. 13 1. 63 41 10 87.

We claim as our invention: 1. A high-speed steel free of chromium in excess of 1.50% of the iron content, and of sub- 25 stantially the following composition: carbon, 0.28 to,,1.02%; vanadium, 0.242.74%; molybdenum, 4.70-9.39%; copper, 0.09-3.91%; nickel, 0.44- 2.35%; boron, 0.05-0.78%; and iron, 94.06-78.25%.

2. A high-speed steel free of chromium in ex- 30 cess of 1.50% of the iron content, and of substantially the following composition: carbon, 0.36-1.03% vanadium, 0.42-2.66%; molybdenum, 5.69-8.61%; copper, 1.50-3.58%; nickel, 0.41- 2.32%; boron, 0.10-'0.39%; iron, 90.71-84.75%.

3. A high-speed steel free of chromium in ex- 5 cess of 1.50% of the iron content, and of substantially the following composition: carbon, 0.36-0.51%; vanadium, 0.42-0.75%; molybdenum, 5.697.74%; copper, 1.50-1.67%; nickel, 0.93-

2.32%; boron, 0.28-0.39%; and iron, 90.71-86.73%.

4. A high-speed steel free of chromium in excess of 1.50% of the iron content, and of substantially the following composition: carbon, 0.36%; vanadium, 0.42%; molybdenum, 5.69%; copper, 1.50%; nickel, 0.93%; boron, 0.39%; and iron, 90.71%.

5. A high-speed steel free of chromium in excess of 1.50% of the iron content, and of substantially the following composition: carbon, 0.64-1.03%; vanadium, OBS-2.66%; molybdenum, 2o 6.69-8.61%; copper, 1.63-3.58%; nickel, 0.41- 1.72%; boron, 0.10-0.24%; and iron, 87.73-84.75%.

6. A high-speed steel free of chromium in ex-, cess of 1.50% of the iron content, and of substantially the following composition: carbon, 0.64%; vanadium, 1.35%; molybdenum, 8.61%; copper, 2.98%; nickel, 1.45%; boron, 0.21%; and iron, 84.75%.

ELMER B. WELCH. LEWIS GERALD FIRTH. 

